1. Field of the Invention
The present invention relates to an information recording medium and an information recording and reproducing apparatus that allow recording of information by irradiation with an energy beam. The present invention relates particularly to an information recording medium that realizes a plurality of methods of record mark arrangement on a substrate in a single format and an information recording and reproducing apparatus that realizes the plurality of methods of record mark arrangement.
2. Related Arts
Information recording and reproducing apparatus heretofore well known include the following two types of apparatus: first, the “DVD specifications for Rewritable Disc (DVD-RAM) Part 1 PHYSICAL SPECIFICATIONS version 1.0” (November 1998) (hereinafter referred to as an article 1 (DVD-RAM)) and second, the “DVD Specifications for Recordable Disc (DVD-R) Part 1 PHYSICAL SPECIFICATIONS version 1.0” (September 1999) (hereinafter referred to as an article 2 (DVD-R)). DVD-RAM stands for Digital Video Random Access Memory, while DVD-R stands for Digital Video Disc-Recordable.
Sector structure of the article 1 (DVD-RAM) has the following characteristics. A sector of the article 1 (DVD-RAM) has a sector structure with a prepit ID, and a land and a groove forming a recording track meander (wobble). In addition, the sector structure employs an integrated address system in which address information of the sector is disposed at the head of the sector as a prepit. The integrated address is followed by a data field for storing user data; a buffer, a guard, and a VFO field situated before the data field; and a guard and a buffer situated after the data field. Incidentally, a prepit integrated address of DVD-RAM is referred to as a CAPA (Complimentary Allocated Prepit Address).
Sector structure of the article 2 (DVD-R) has the following characteristics. A groove that forms a recording track of a sector of the article 2 (DVD-R) meanders (wobbles), and land prepits are periodically disposed in a land. According to the method of the article 2, the period of wobbling is accurately detected by a groove wobbling signal and a land prepit detection signal, and then timing in recording is determined with reference to the period of wobbling. As for address information, an address of a single ECC block is distributed over 16 sectors, and is recorded as a prepit in a land prepit of each of the sectors within the single ECC block.
According to the typical methods described above, a self-oscillator corrects the phase of a recording clock by detecting a wobbling signal, or a recording clock is generated by frequency conversion of the wobbling signal. Thus, a recording clock dependent on the wobbling signal is generated in some cases.
According to the conventional information recording media and information recording and reproducing methods, when the method of record mark arrangement in a track is changed, the physical format of the disk is also changed, as in the case of switching between a DVD-R and a DVD-RAM, for example. This makes it difficult to ensure compatibility between pieces of data recorded by a plurality of different methods of record mark arrangement.
Specifically, the DVD-RAM has the CAPA, and therefore user data is not provided in a physically continuous arrangement, while the DVD-R has physically continuous user data, as in the case of the DVD-ROM. Therefore, the different methods of record mark arrangement make it impossible to record information on a DVD-RAM medium by the same procedure as that of the DVD-R, for example, and thus make it difficult to ensure compatibility of recorded data.
Moreover, in the examples described above, since frequency of the wobbling detection signal is considerably lower than that of the recording clock, a slight detection error in the wobbling detection signal results in significant errors in the frequency and phase of the recording clock. When such a recording clock is used in recording, record marks to be written are not necessarily written reliably at specified positions on the disk. Therefore, in the case of DVD-RAM, in order to allow for such errors in the recording clock, length of a recording area within a sector is made somewhat longer than that of a recording area actually used for recording, thereby somewhat decreasing its recording density. In the case of DVD-R, data becomes discontinuous at a linking portion, and thereby a linking loss is caused.